A Reddit usor tardius rettulit I/O in suis btrfs systematis post adaequationem nuclei versionis 5.10.
Regressionem repetendi modum simplicissimum inveni, nempe extrahendo tarball ingentem, exempli gratia: tar xf firefox-84.0.source.tar.zst. In externa mea USB3 SSD in Ryzen 5950x accepit ab ~15s in 5.9 nucleo ad fere 5 minuta in 5.10! Distributio systematis fasciculi excludendi, novam quoque notam, antea insuetam 4.0TB Plu 1 SSD, probavi, simili, etsi non minus abhorrens regressus ab 5.2s ad a whopping ~34 secundis vel ~650% in 5.10 :-/.
Hoc referri videtur ad Related News in btrfs exactoris.
Nuntius de procedere in Linux-btrfs list Mailing.
Source: linux.org.ru